The present invention relates to wind-propelled vehicles, and particularly to light-weight soft wing-sails for propelling such vehicles. The invention is especially useful in water vehicles, and is therefore described below with respect to such application, but it will be appreciated that the invention could also be used in other applications, such as for propelling vehicles over land or ice.
In recent years, a number of soft wing-sails have been proposed in order to better exploit the wind forces for propelling the vehicle. Examples of various constructions of soft wing-sails heretofore proposed are described in Fuller U.S. Pat. No. 4,685,410; Magrini U.S. Pat. No. 5,271,349; Milidragivic U.S. Pat. No. 5,868,092; Gonen U.S. Pat. No. 6,863,008; and in U.K. Patent Spencer 2,008,514.
However, the main disadvantages of the structure of soft wing-sails proposed were cumbersome and/or heavy structure that is hard to use and to fix damages at sea and, has negative effects on boats stability and performance. Also, complicated structure with many moving parts tends to jam and stick and therefore is less safe at sea.
There is therefore a definite need for a simple and light weight soft wing-sail structure, having very few moving parts, permitting hoisting and reefing each of the sail panels independently and providing all the benefits of a wing-sail over standard sails.